1. Field of the Invention
This invention relates to an improvement on a contact shutter device in which contacts are pressed as to be displaced backward and downward by a lowering movement of the contact shutter device mounted on a socket body in order to cancel a contact relation with an IC package.
2. Brief Description of the Prior Art
In Japanese Utility Model Early Laid-open Publication No. Sho 62-111673, the contact is provided with a contacting piece portion formed on an upper end of a curved spring piece, and this contacting piece portion is pressed so as to be displaced backward and downward by the lowering movement of a contact shutter member so that its contact relation with a terminal member of an IC package would be broken.
The above-mentioned prior art aims at mounting and removing the IC package with ease by displacing the contacting piece portion of the contact backward and downward and bringing it to a position where the contacting piece portion of the contact would not interfere with the terminal member of the IC package to release the restraint of the IC package. With the above-mentioned construction of the prior art, however, a lot of useless components of forces for vertically pushing down the contacting piece portion are generated when the contacting piece portion is pushed down, and the push-down force cannot be favorably converted to a backward and downward displacement of the contact. The curved spring piece does not effectively contribute to the backward and downward displacement of the contact. Moreover, there is a fear that excessive generation of components of the vertical push-down force causes the contact to be deformed.
It also has problems such as the excessive push-down force to the shutter member jeopardizing the smooth operation of the device.
There is also proposed another example wherein the contact is provided with a pressing force receiving portion by a contact shutter member projecting from a waist portion below the contacting piece portion of the contact, as disclosed, for example, in Japanese Patent Early Laid-open Publication No. Sho 62-93964. However, as the rigidity becomes extremely high on the side of the contact which is fixedly embedded, the push-down operation of the shutter member becomes very heavy for a socket having many poles, and a space for inserting the push-down portion of the shutter member deep into the back of the contact is required, thus resulting in a large size of the device.